Xin LI 82cf92d483 Add locking around access to parent node, and bail out when the parent
node is already freed rather than panicking the system.

PR:		kern/122038
Submitted by:	gk
Tested by:	pho
MFC after:	1 week
2009-10-11 07:03:56 +00:00
..
2009-09-30 18:50:50 +00:00